Dec., 1934
COMMUNICATIONS TO THE EDITOR
THE TRITYLATION OF SUGAR MERCAPTALS
Sir: In view of the publication of Micheel and Spruck [Ber., 67, 1665 (1934)J on the tritylation of galactose ethyl mercaptal, we wish to report the work completed in this Laboratory on the tritylation of a number of sugar mercaptals. The work herein reported was completed before the above article of Micheel and Spruck appeared and was also well under way before the publication of Micheel and Suckfull [Ann., 502, 85 (1933)] on the action of mercuric chloride on 6iodogalactose ethyl mercaptal tetraacetate. All compounds now reported were obtained in crystalline form and were recrystallized to constant melting point and rotation. All rotations are recorded in U. S. P. chloroform. &Glucose ethyl mercaptal was successively treated in pyridine solution with triphenylchloromethane (trityl chloride) and benzoyl chIoride to produce (I) 6tritylglucose ethyl mercaptal tetrabenzoate (m. p. This tritylation proce161-162', [a]D f49'). dure was originally applied to carbohydrates by Helferich and co-workers [B. Helferich and J. Becker, Ann., 440, 1 (1924)l. Similar procedures produced the tetrabenzoate of 6-trityld-galactose ethyl mercaptal (m. p. 138-139'; [.ID -22.5'). By substituting acetic anhydride for the benzoyl chloride there was obtained 6-tritylgalactose ethyl mercaptal tetraacetate (m. p. 123-124'; [a]D -22.5'), trityl-Z-arabinose ethyl mercaptal triacetate (m. p. 101-102'; TalD -24'), and trityl-d-xylose ethyl mercaptal triacetate (m. p. 149-150'; [a]D -20.5'). Attempts to hydrolyze the trityl group in 6tritylglucose ethyl mercaptal tetrabenzoate with hydrogen bromide always produced (11) 6-bromoglucose ethyl mercaptal tetrabenzoate (m. p. 169-170'; [ . I D 4-39"). The position of the bromine atom was proved by the identity of this compound with the product obtained by benzoylation of the 6-bromoglucose ethyl mercaptal of E. Fischer [E. Fischer, B. Helferich and P. Ostmann, Ber., 58, 873 (1920)l. Iodine replacement of the bromine atom was effected by sodium iodide in acetone 0. C. Irvine and J. W. Oldham, J . Chem. Soc., 127, 2729 (1925)] to produce (111) 6-iodoglucose ethyl mercaptal tetrabenzoate (m. p. 165-166'; [.ID f39') with constants practically identical with those of the 6-bromo compound. The iodine was removed with silver nitrate in dilute acetone and the mercaptal groups with
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mercuric chloride and cadmium carbonate in moist acetone [M. L. Wolfrom, THISJOURNAL, 51, 2188 (1929)l. The product obtained was the glucopyranose tetrabenzoate of E. Fischer [E. Fischer and H. Noth, Ber., 51, 321 (1918)] and a benzoyl migration had accordingly occurred. Cautious hydrolysis of 6-tritylgalactose ethyl mercaptal tetraacetate with hydrogen bromide produced 6-hydroxygalactose ethyl mercaptal tetraacetate (m. p. 96-97"; [a]D -7'). More vigorous hydrolysis produced 6-bromogalactose ethyl mercaptal tetraacetate (m. p. 110-1 11'). Removal of the mercaptal groups from 6-hydroxygalactose ethyl mercaptal produced the galactose 2,3,4,5-tetraacetate hydrate of Micheel and Suckfull. When recrystallized from water this substance melts sharply at 168'. Removal of the mercaptal groups from 6-tritylgalactose ethyl mercaptal tetraacetate produced 6-tritylgalactose tetraacetate, isolated as a compound with one mole of ethanol (m. p. 153'; D I . [ -28') and also as its semicarbazone ([.ID +ZOO).
The above work on the glucose compounds was presented completely on March 30, 1934, at the 44th Meeting of the Ohio Academy of Science at Columbus, Ohio. Compounds I, I1 and I11 are recorded in the M.A. thesis of Mr. Clarence C. Christman, The Ohio State University, Dec. 1.5, 1933. Full details of all this work will be published a t a later date. DEPARTMENT OF CHEMISTRY M. L. WOLFROM OHIOSTATECOLLEGE JOSEPHL. QUI" COLUMBUS, OHIO CLARENCE C. CHRISTMAN RECEIVED NOVEMBER 21, 1934
CRYSTALLINE 8-GLUCOHEPTOSE AND ITS MUTAROTATION
Sir: A sirup containing 8-glucoheptose was synthesized by E. Fischer [Ann.,270, 87 (1892)] but he and subsequent workers were unable to obtain the crystalline sugar. The writer has now prepared B-glucoheptose in crystalline form. The mutarotation is very unusual and resembles that of ribose, reported in a previous publication [THIS JOURNAL, 56,747 (1934)l. The first crystals separated spontaneously from a product obtained by Fischer's method from 6glucoheptonic y-lactone by reduction with sodium amalgam. The new sugar crystallizes in slender prisms, melting a t 121°, very soluble in water but
